My U.S. Pat. No. 6,018,143, entitled Heat Thermal Bag, issued on Jan. 25, 2000 discloses a portable heating container or thermal bag for carrying a food product such as a pizza. The thermal bag has top and bottom panels and is closed at the rear end and at the sides, but has an opening at the front for the insertion and removal of the food product. The bag is insulated and has a built-in heating device with a thermostat to maintain the bag at a desired temperature. The heating device is intended to be plugged into the cigarette lighter of the delivery vehicle so that the bag remains heated up to the point of actual delivery to the customer. Thus, the pizza or other food product in the bag will remain oven hot no matter what weather conditions, traffic conditions or delivery distance prevail. A thermofuse is employed to prevent overheating as might occur as a result of failure of the thermostat.
When properly used, the thermal bag described above will maintain a constant temperature of 160 degrees Fahrenheit to 175 degrees Fahrenheit so that the food product is maintained at a desired temperature while being transported from one location to another. If not properly used, however, the temperature of the thermal bag can drop resulting in the food product not being maintained at the desired temperature when delivered to the customer. This, of course, affects the quality of the food product and often creates an unhappy customer who may decide to no longer make any additional purchases from the party preparing and selling the food product.
Accordingly, one object of the present invention is to provide a new and improved seal for a food container that renders the food container tamper-proof and serves to visually indicate to a customer that the food container has been maintained in a heated state.
Another object of the present invention is to provide a new and improved portable food container for carrying a heated food product for delivery to a customer and in which the container is provided with a seal that will require the container to be maintained at a desired temperature.
A further object of the present invention is to provide a new and improved portable food container for heated food products that is provided with a seal which prevents tampering with the contents of the container and also serves to verify visually that the container is at or above a desired temperature.
A still further object of the present invention is to provide a new and improved method of transporting a heated food product in a portable food container from the place where the food has been prepared to the customer's door while maintaining the food container at a constant temperature and ensuring visually that the contents of the food container is at or above a desired temperature when given to the customer.
A still further object of the present invention is to provide a new and improved method of ensuring that a portable food container carrying a heated food product is not tampered with and is at a desired temperature after being transported by a motor vehicle from the store where it was prepared to a customer's door.